Bullvalene Trisepoxide and Its Stereospecific Rearrangement to 2,8,12-Trioxahexacyclo[8.3.0.0<sup>3,9</sup>0<sup>4,6</sup>0<sup>5,13</sup>0<sup>7,11</sup>]tridecane: Two New<i>C</i><sub>3</sub>-Symmetrical Oligocycles with Propeller Chirality
作者:Shelue Liang、Chi-Hung Lee、Sergei I. Kozhushkov、Dmitrii S. Yufit、Judith A. K. Howard、Kathrin Meindl、Stephan Rühl、Chiyo Yamamoto、Yoshio Okamoto、Peter R. Schreiner、B. Christopher Rinderspacher、Armin de Meijere
DOI:10.1002/chem.200401027
日期:2005.3.18
CHCl(3)) (secondly eluting enantiomer). The absolute configuration of (-)-8 was determined by anomalous diffraction to be (1R,3R,7R,9R,11R,13R). DFT computations at the TD-B3 LYP/6-31+G(d,p)//B3 LYP/6-31+G(d) level of theory for (3R,5S,7S,9R,11R,13S)-6 and (1R,3R,7R,9R,11R,13R)-8 predicted specific rotations of -206.7 and -83.4, respectively. Acid-catalyzed isomerization of the enantiomerically pure (+)-6
用中和的Oxone溶液将Bullvalene(1)环氧化,得到消旋的三环氧化物rac-6,分离产率为93%。通过X射线晶体学检查其结构。通过制备型HPLC分离两种6的对映异构体,并显示出α(25)(D)= + 160,α(25)(365)= + 567(c = 0.946,CHCl(3))的比旋光度。对于第一次洗脱的对映异构体,α(25)(D)=-157,α(25)(365)=-554(c = 0.986,CHCl 3);(+ )-6和(-)-6的绝对构型分别通过X射线晶体结构分析和异常衍射确定。据此,(-)-6具有(3R,5S,7S,9R,11R,13S)-,(+)-6具有(3S,5R,7R,9S,11S,13R)-构型。在-78摄氏度下用BF(3)Et(2)O处理后,X射线晶体结构分析证明,三环氧化物rac-6重排并保留了骨架三元碳环,得到笼型三醚rac-8,几乎可以定量收率。通过制备